Terminal
by TheTrashCansRevenge
Summary: After years of neglect and abuse, things start to take a dark turn for Sans. (Underfell!AU) All characters belong to Toby Fox and the owner of the Underfell AU
1. Prologue

Summary: After years of abuse and neglect, things take a dark turn for Sans. (Underfell)

prologue

 _When a monster is close to 'falling down' they go through a series of different stages depending on the monster's HP, but it all comes down to eight main stages. First, they have fierce coughing fits, and can be mistaken for the flu._

 _The next stage is the loss or near loss of voice, which can be dismissed easily by those who don't check the inflicted monster's HP._

 _The third stage is the decrease in magic/magical abilities, which may affect the inflicted monster's physical appearance and mental state._

 _The fourth stage is the loss or near loss of eyesight, and can cause the sequence of falling down or self destruction to happen quicker or easier._

 _The fifth stage is the isolation of one's self, and nightmares from previous memories. These two happen simultaneously, in addition with stages 1 through 4. Some call the nightmare bit '5.5' since it happens overnight instead of 24 hours. During these nightmares, the inflicted monster will not be able to wake up, until someone else wakes them up instead._

 _The sixth stage is the loss or near loss of hearing, which may cause the victim to self destruct rather than fall down. Also, it is harder to wake up the victim from a nightmare, and can cause a comatose, which would slightly increase the victim's life, but this does not stop the inevitable._

 _The seventh stage is the sense of getting affairs together and extreme hopelessness. The victim would complete tasks that they haven't done before the sequence of falling down, although some call this part not a stage, but acceptance._

 _The eight is finally falling down._

 _From the Journal of Dr. Alphys_

 _Information from Project Determination_


	2. Chapter 1

Chapter 1

Stage 1

Snowdin was quiet at night. The snow would fall, the stones in the ceiling would sparkle, and all was calm. This was the only time it was peaceful in the Underground.

However, as it might seem peaceful on the outside, it was definitely not the latter inside a certain log cabin located at the edge of the snowy village. There, a certain monster was sleeping on the floor; no blanket or pillow. The bedroom around him was a mess. There were greasy clothes that littered the floor, and a trash mountain that had become a self sustaining tornado.

The walls and doors of the room has seen better days. They were littered with various sized holes and cracks, hinting various lost fights and arguments gone sour. The window was nothing more than an old t-shirt pinned to the wall. It was not effective, and still let Snowdin's cold air permeate the room.

The occupant of the room, well, was a mess. An old black hoodie was folded to the right of the occupant, who was wearing a red t-shirt and sweatpants covered in grease, dirt, and dust. The occupant's arms were scattered with various scars and fractures.

You, the reader, has probably figured out who exactly the occupant is by now…

...If you don't, it's Sans.

In his left hand he held a shard of broken glass, probably salvaged from the broken window. It was covered in some sort of red liquid and dust. It's sharp edges have cut into his hands, causing it to bleed continuously through the night.

Sans woke up with a start, and started having a coughing fit. It sounded raspy, and made his throat hurt. He tried to muffle his coughs, as too not wake the other occupant of the house. The sound of stomping soon mixed with the sound of coughs. The door slammed open, revealing the second in command of the royal guard, and he was obviously furious. " KEEP IT DOWN, DAMMIT!," he yelled, and Sans just shot him a death glare. " well, i'm sorry, i can't fuckin' help it," he said quietly, and Papyrus stormed back into his room. Not wanting to invoke his brother's wrath, he slipped on his black jacket, and teleported outside.

Instead of landing on the ground, he ended up teleporting ten feet in the air. " oh, shi-"

He landed face first in the snow. Thankfully, it had snowed yesterday. Groaning, he pulled himself out, and headed towards his secret lab. No one else but him knew of this hidden lab, and he intends to keep it that way. In one of the drawers was some cough medicine, which he took a small sip of, and immediately spat it out. " ugh, it's expired.," he said tossing the medicine into a garbage bin. He tried to stifle another fit of coughs, thanking that the walls of the lab were sound proof. He was mildly surprised when the floor of the lab splattered with his own blood.

'Damn, that's gonna be a pain in the rear to clean out.," he grumbled, and opened another drawer. Inside was a pack of old hospital masks. Taking one out of the package, he slipped a wraparound mask on. He walked around the lab until he found an old pen and notepad. He wrote down 'visit alphys for medicine'. He went over to the door and looked outside. The various shop lights that were on told him that it was time for him to rush to his sentry post. He subconsciously rubbed his nonexistent throat, and headed towards his post.

Halfway towards his post, however, he started having a particularly nasty coughing fit. A nearby monster, Snowdrake to be exact, looked at him in horror, and started backing away from Sans slowly. Confused, Sans put his hand up to his mouth, and when he pulled away, his entire hand was soaked in blood. Sighing, he wiped his hand on the side of his pants, staining it with blood. After being abused almost every other day, he had found that he had become numb to most pain. He arrived at his sentry post, and his coughing fits getting slightly worse as time went. Soon, the blood was dripping down his chin, earning him several horrified glances.

He heard his phone ring from the depths of his coat pocket. Looking at the caller ID, he picked up, only to hear a familiar stuttering voice.

" H-holy HELL! Y-you look l-like you murdered someone!," the voice said. The voice belonged to a small yellow lizard monster, the Royal Scientist of the Underground.

" what do you want, alphys."

" W-Well, I c-couldn't help b-but notice your, ah, condition. Could y-you, um, y'know, swing by when you get the chance?," she said.

" sure, i'll come by on my next break," he said, and hung up on her. Soon, he noticed a tall figure coming towards him. " WELL, IT'S GOOD TO SEE YOU AREN'T SLACKING AS USU-," Papyrus said, but paused when he saw Sans' face. " SANS! WHAT IS WITH ALL THIS BLOOD?!," he exclaimed, clearly borderline disgusted and horrified. " it's nothing, boss. I'm gonna see alphys later on.," he said, with the most utter 'I'm-pretty-much-sick-of-your-shit-bro' look on his face he could conjure up with his bloody mask.

" LATER?! YOU ARE TO GO SEE HER RIGHT AWAY!"

"Wait, what?," Sans said. His brother usually never cares for him, but this is just downright strange. " um, what about my-"

" JUST GO, FOR CRIPES SAKE!"

" er, yes boss"

Sans walked towards the boatman. He wondered why Papyrus looked horrified. He got beaten up everyday, so he has seen blood before.

He unconsciously rubbed his right arm, lifting his jacket fabric just high enough to show his scarred bones. He realized that he had already walked past the boatman, so he backtracked towards the dock.

" _Where To?,"_ the boatman said with his brittle raspy voice.

" hot-," Sans was cut off by a another bout of bloody cough. " hot- _cough-_ land.," he managed to say, and the boat then took off towards the land of fiery magma and brimstone.

* * *

Alphys was sitting at her lab desk watching vore when she heard a faint coughing followed by two hard knocks. She closed-no- slammed her laptop shut, and went over to the door. The hydraulic pressure doors open, revealing a very bloody and sick skeleton.

" Ah, good, y-you're here!," she said, and Sans just stood there silently. "Come, I-I need t-to analyze y-you and your stats in order to see if my s-suspicions are correct.," she said, and pulled out a chair from who knows where. "S-sans, may I see your s-stats?," she asked.

Sans, who was having another coughing fit, managed to pull up his stat screen. Alphys did not like what she saw.

"what?," Sans said, confused at Alphys' horrified expression, which soon turned to nervous laughter. "what the hell are you laughing at?"

" Uh, h-how long h-have you been, er, hurt by yourself and y-your boss?," Alphys inquired.

"dunno. awhile, i guess."

"...Wow. W-well, however long it w-was, it's t-taking a t-toll on you.," Alphys said, still nervously chuckling. " W-well, I'm n-not gonna mess w-with determination on y-you, so, I'm j-just gonna g-give you this, uh, cough s-syrup to help out with your, er, condition.," she said, digging around on her desk until she found a bottle deftly labeled "cough syrup" and a packet splattered with a strange red liquid. " You m-might want t-to read this.," she said, thrusting the items into Sans arms. He quickly scanned the stained paper, his smile turning into one of grimace.

"...alphys?"

"I-i'm sorry, b-but, er, you, you're dying. I d-don't know if you want to try t-to fix it, or, y'know, end yourself quietly v-via mercy k-killing, or-"

"...just don't tell my boss.," he said, and Alphys nodded in understanding.

* * *

"SANS, WHAT TOOK YOU SO LONG?"

He had decided to walk all the way back to Snowdin in order to get some of his thoughts straightened out. It was now darker than usual in the underground, and Papyrus was already at the house. "UNDYNE CALLED ME TODAY," he said, and Sans mentally cringed. Alphys must have told Undyne, and if Undyne told Papyrus… Sans was sweating bullets at this point. Thankfully, the medicine Alphys gave him relieved his cough, but he still had fits.

" SHE SAID TO EXCUSE YOU FROM YOUR WORK FOR THE TIME BEING, BUT SHE NEVER TOLD ME WHY.," he said, and Sans was slightly relieved. " guess alphys told her of my condition," he said, hoping that he wouldn't ask any questions.

"TCH! I GUESS YOU'LL STAY AT HOME UNTIL YOU GET BETTER!," he said dismissively, and walked to his room. Once Sans was sure the door to his room was closed all the way, he started grabbing some trivial things. His quantum physics/joke book, his telescope, and an old faded photo of him and a few other people. The photo was so faded, the faces seemed blurry, but anyone could see that the group consisted of three people.

"...things were better back then…," he said, and quietly exited the household. He headed to a secluded area in Snowdin, a place only he knew. It was a quiet little cove with glowing blue mushrooms and blue water similar to Waterfall's numerous luminescent lakes. Setting down his possessions, he assembled them in a way a monster would set up the funeral for a loved one.

"Heh, of all things i'd never thought i'd do would be making my own grave.," he whispered hoarsely. He teleported to Waterfall, nearly landing in the water, and searched for an echo flower.

He soon found one, and carefully uprooted it up, and took it back to the cove, opting to walk rather than teleporting. He whispered a speech, one that sounds very well rehearsed, and planted the echo flower down into the earth.

* * *

A/N: Greetings to anyone who is reading this! I am a relatively new writer, but I am no stranger to this website. I will accept helpful constructive criticism, and please no flames. I will update this almost every week, but sometimes it will take longer to find a muse.

Or I'm too lazy to type.

Well, I hope you would enjoy this angsty piece of work

Ciao!


	3. Chapter 2

Chapter 2

Stage 2

Sans did not sleep easily that night. Along with his coughing fits, he found it hard to speak, despite not having any vocal chords. He kept thinking of his last days, his boss, and his gradually decreasing HP.

He thought of the 'grave' he had made with himself. Sitting up off the floor, he thought about having a quiet passing, how his boss would react if he had suddenly gone missing, and if his boss accidently stumbles across his dust.

He pondered this morbid thought for a while, until the first rays of artificial light that lit up the underground peeked through. Getting up, he went out of the house before Papyrus could wake up.

Sans was soon met by Greater Dog, the biggest sentry in the Snowdin area. Greater Dog growled at Sans, who retaliated with a short lived glare, followed by a series of hacking coughs. Confused by the noise, Greater Dog bounded away, albeit back into a snow poff.

* * *

Sans soon came to his sentry station. Usually, he would take a nice long swig of mustard, but today, he didn't feel as hungry. Even if he did, he knew that he would just cough it back up.

He shuddered at the thought.

He then heard someone heading towards him. It was a heavily armoured figure, about six feet tall, and was holding a spear longer than he was.

" 'sup undyne," he whispered in a crackly voice that could rival the Boatman's. "What the hell are you doing out here. You are supposed to stay inside your house.," she said, her tone resembling someone who'd scold a Froggit. " welp, i never got the memo.," he whispered, and Undyne leaned over to his sentry station.

" Don't even play dumb with me, punk. Alphys told me of your condition. Hell, I even took the liberty of not telling Papyrus.," she growled, obviously furious at his stubbornness. "why do you even care.," he whispered, " suddenly i'm dying, and that's the only time anyone would give a fuck. so, why, of all people, undyne, would you care about the well being of a weak, pathetic, and to top it all off, _useless_ , monster like me.," he snapped, causing Undyne to back off.

After a period of silence, Undyne spoke.

" I respected you, knowing all the shit you have to go through everyday. I thought you were strong…," she said. " Here I thought you'd actually fight, and try to get better." She started to walk away. "Guess I'm wrong.," she said, and went back to Waterfall.

* * *

Undyne sat down at her table. ' Damn, guy has a death wish.,' she thought, brewing herself a cup of golden flower tea. She sipped it casually, thinking of something Papyrus and herself had talked about, when Papyrus joined the Royal Guard.

 _Flashback_

" _HELLO UNDYNE…"_

" _Hey, what's wrong?," she asked, filing away papers into a file cabinet. " SANS ISN'T ACTING LIKE HIS USUAL SELF TODAY…," he said, looking extremely worried. " Maybe he's having a bad day."_

" _NO, IT'S NOT LIKE THAT! HIS HP HAS LOWERED QUITE A BIT, HE'S GETTING LAZIER AND LAZIER EVERYDAY, AND HE KEEPS MUTTERING ABOUT SOME SORT OF ANOMALY AND TIMELINES.," he stated. Undyne looked at him. "Maybe good training?," she suggested._

" _UNDYNE, WHAT IF HE, ER...FALLS DOWN?!," he said. Undyne rolled her eye. " I wouldn't worry about it, Papyrus. Your brother is a pretty strong. Heck, I wouldn't be surprised if he went back to his old self in no time!"_

 _Flashback over_

She sighed, gulping down the rest of the golden flower tea, not minding the scalding burn it left behind. 'Maybe that's what happened,' she thought. 'Maybe this is like a burn that an event left behind…'

Surprisingly, it made some sense to her.

* * *

It was almost evening in the Underground. Sans trudged through the snow, trying to think over what he had said to Undyne earlier. Taking a slight detour, he went to the secret cove. He sat down next to his belongings, careful not to disturb the echo flower. ' ...heh. people wouldn't even notice if i'm gone.,' he thought bitterly. 'everyone would be better off without me. weak monsters like me don't have a place in this hell.'

He checked the time on his phone. The dimmed cracked screen managed to show the numbers '19:30 '. He shoved his phone back in his pocket, his fingers getting slightly cut from the uneven screen edges. Sighing quietly, he brought out his SOUL, and started to inspect the inverted heart.

It was a dull white, and had several cracks that littered the edges. He looked at his stats.

His HP had permanently lowered to 0.7/0.7. Alphys had written as a side note in her report that monsters that were falling down would gradually lose their HP. He made a mental note to avoid sparring Papyrus or anyone for the matter at any costs.

A small chime emitted from his pocket, signaling him that his shift was over. He turned off the alarm, and headed home.

* * *

A/N: Heya! Soo, I know I mentioned above that I would be updating every week or so,,,BUT I see I have TWO followers, and I just had to write down chapter two!0w0

Anyways, thank you for following my story, you have no idea how much this makes me happy!

Red: jeez, the shit you put me through…

BC: Shush! The story shall go on! Ciao!


	4. Chapter 3

Chapter three

Stage three

 _Bzzzt! Bzzzt!_

Grumbling, Sans answered his phone. " who the hell calls at this time of night," he said, his voice barely audible. Looking at the caller id, he began to listen to the Royal Pain.

" S-sans, are you f-feeling odd by any chance? Y-y'know, like tired than usual?"

"... Oh, I-I forgot about you n-not being able to be audible, but could you come over to the lab?"

She hung up, and Sans plopped down on the floor. He did not want to get up, and he really did not want to walk all the way to hotland. But, it had to be done.

Sort of like midterms.

He got out of his room, not bothering to grab his jacket. He had to get out quietly, or else his brother would catch him. He was halfway out of waterfall when he noticed something odd. He had peered down to the luminous blue water, and backed away in shock. His usually red eye had grown dimmer, almost to the point where it blended with his black eye sockets. At that moment, Sans knew he was screwed.

* * *

He quickly arrived at Alphys' lab, only to see no trace of the young scientist. He went towards a door that looked like a personal bathroom. On the door was a note.

 _Sans,_

 _I am at the bottom floor of my lab. This door leads to an elevator_

Pocketing the note, Sans went to the bottom floor, per Alpys' instruction. He had seen the amalgamates, but Alphys had threatened to blackmail him if he ever told a living soul. It's not like he cared or anything, he didn't want his brother to kill him for allowing Alphys to blackmail him.

After taking several wrong turns, he finally found Alphys. Next to her was a hospital bed with an occupant, a surgical lamp, and a tray table with several instruments. Her back was turned, and she seemed to be very busy on her subject.

"Ah, I see t-that you have arrived.," she said, turning towards him. " H-holy hell, y-you look terrible!," she grinned, and Sans just rolled his eyes. " Anyways, remember when I was y-younger, I always w-wanted to make a S-SOUL powered robot?," she said, turning back to her work. " All I n-need is the Soul of a B-boss monster…," she trailed off.

"what does that have to do with me?," Sans whispered hoarsely. Alphys looked at him with a crazed expression. " Isn't it obvious? I need your Soul."

Sans backed away in shock. "what do you mean, my SOUL?"

"Did I fucking stutter? I _need your SOUL."_

Sans subconciuosly put his hand over his chest. "what are you going to do, kill me right now?," he growled, and Alphys shook her head. "Oh, n-no! I-i am simply going to wait until you die!," she said in a sickening cheery attitude. "Y-you see, once you die, I'm g-going to take your SOUL once your body falls apart, a-and use it in m-my experiment!," she said, and Sans looked at her in confusion.

" how are you even going to get my SOUL and contain it? Monsters can't absorb each other's SOULs."

" Simple! I just use a SOUL c-canister!," she said. Sans looked at her in confusion. " aren't those used for _human_ SOULs?," he said skeptically, and Alphys rolled her eyes. " I w-wouldn't use it if I didn't t-test it first!," she said, revealing another canister underneath the bed. Inside was a glowing white SOUL that looked like it was half a second away from oblivion. " D-do you know how hard it is to c-catch a SOUL from a normal monster?," she said darkly.

"...fairly hard?"

Alphys face palmed. " Okay wise guy, I need to know where you plan on dying.," she said impatiently.

* * *

Soon, they have arrived at the secret place in Snowdin. Alphys looked at the pile of items, and picked up the Quantum Physic/joke book. " S-seriously?," she said, and put it down as Sans shrugged.

Alphys took the canister, and set it beside the pile. " Okay, when you are about to, er, die, uh c-call me…," she said, and laughed. " Wow, that sounded morbid.," she said. Suddenly, her phone started ringing. " Oh, g-goodness…," she said, and looked at the caller ID. "Oh g-goodness! It's Papyrus!," she screamed, and picked up.

" H-hello?," her voice hitched in panic. " ALPHYS, WHERE IS SANS? I TRIED TO FIND HIM, BUT HE LEFT SOMETIME EARLY IN THE MORNING, SURPRISINGLY, I DIDN'T EVEN KNOW HE COULD WAKE UP THAT EARLY...BUT ANYWAYS, HE LEFT HIS JACKET AND PHONE AT HOME, AND I WAS WONDERING IF HE WAS WITH YOU.," his voice could be heard by the both of them, and it wasn't even on speaker.

Alphys looked at Sans, who rapidly shook his head. " Er, n-no, S-sans isn't with me, I'llcallyouwhenIseehimBYE.," she said rapidly, and promptly hung up.

"well, isn't that suspicious.," Sans muttered. Alphys facepalmed the facepalm of all facepalms.

" UGH… Y-you could stay at the lab..," she grumbled.

* * *

A/N: And end scene! Wow, i like how that went, let's post it!

Alphys: Can I take t-this make up off? It's i-irritating my scales…

Red: ugh, im going on a lunch break * leaves*

BC: Weell, that all for now! Tune in next week, and thanks to Wonkie, Nikki-Ai-Chan, VioletAssassin1124, and SidraNova! If you guys want to have an oc or muse featured in about chapter seven, just leave a review asking! You guys are the real MVP!

Ciao!


	5. Chapter 4

Chapter 4

From a different point of view

Papyrus paced around the house, waiting for Sans to come home. It may nt seem like it, but he cared for his brother.

He just had different ways of expressing it.

He had noticed Sans condition, and was terrified. The one and only fer the Great and Terrible Papyrus had: abandonment. He was terrified that his brother would be put in Alphys' Lab for a long time until he healed. He felt that it would take a long time, too.

He glanced at the phone at the table, thinking about Alphys' quick and suspicious phone call. He knew it in his SOUL that she had Sans at her lab, probably getting tested on and who knows what.

Shuddering, he reached for the phone…

 _At Alphys' lab_

 _MEW MEW! MEW MEW!_

Alphys' phone rang angrily, and she and Sans physically jumped. " Oh _shit,_ it's y-your brother; keep qiet while I a-answer," she whispered, and picked up the phone.

" ALPHYS, HAVE YOU SEEN SANS? HE HASN'T COME HOME YET.," Papyrus said. He sounded a little irritated, and there was a sharp edge in his voice. " Um, n-no! He's n-not here, I t-think he's at…," she looked at Sans, who said 'Grillby's' using hands. " GRILLBY'S! Yeah, He i-is probably at G-grillby's and not at my lab haveanicenightBYE!," she hurriedly hung up.

Sans facepalmed. " . .that.," he said hoarsely, and Alphys shrugged. Her phone rang again, and Alphys threw the phone against the wall, effectively shattering it.

"um, alphys?"

Alphys sighed. " What is it?"

" would it be weird if I said you look sort of blurry?," he asked, and Alphys gasped. "Oh, s-stars, you're already on stage 3… Oh boy…," she grabbed a few blankets out of a closet, and headed towards the basement. Sans followed her, and she walked over to a single bed with wires strewn about it. " Sans, when you sleep tonight, I will be monitoring your dreams. If you experience any nightmares, um, let's just say I would have to wake you up.," she said, in a proffesional manner and without a single stutter. He shrugged, and lay down on the bed.

He saw Alphys put some wires on his head, and he fell fast asleep.

A/N Hey guys, I'm alive! I'm sorry that I haven't been able to upload: there were some issues from the past month that needed to be fixed. Meanwhile, here is a makeup chapter! Part two will be next week! Ciao!


	6. Chapter 5

Chapter 5

Stage 5 and 5.5 but not in that particular order

Sans was alone. All around him was inky black darkness. ' geez, this is one weird dream,' he thought sarcastically. The weirdest part of all was that it felt… real.

Taking a few steps forward, he suddenly was blinded by a flashing light.

He woke up from his bed in Snowdin. " what the [redacted] is going on?!," he said, looking around frantically. It was his same room he woke up in several days ago. He was aware of the world suddenly 'resetting' itself, but _this_? This was just cruel.

He looked down at himself, and there was not a speck of blood on him. Strangely, the scars on his body had mysteriously disappeared as well. He did not notice, however, for he was having a panic attack. ' Was that sickness just… just an ANOMALY?!,' he thought, and he punched a wall. " Is This Some Sort Of Cruel JOKE?!," he yelled, and started sobbing.

He just wanted everything to end. Wiping away tears, he muttered " if the world is so cruel, i might as well end myself… i ...i can't do this shtick anymore…"

Summoning a sharp, broken bone, he pointed it towards himself.

" i just want to be free."

Alphys was sitting next to Sans. As he was sleeping, she had hooked up various machines to his body. She was currently checking a SOUL monitor when she noticed Sans twitching. " What the…"

She also noticed that there was an attack forming just above Sans' SOUL.

" OH SHIT!," she yelped, and dug around in her desk. Inside one of her drawers was a shot filled with a green liquid. It was labelled ' Tranquilizer'.

The attack was becoming more opaque. She had seen this phenomenon with her other test subjects, but Sans was no test subject.

He was a friend.

She plunged the needle straight into his exposed SOUL, praying that she didn't accidently kill him. She injected the green liquid.

Sans' body jolted, but sure enough the attack fizzled out. She sighed in relief, and returned to monitoring her friend.

That night, Sans' was in a dreamless state.


End file.
